Liquid cleansing products are extensively used as hand cleaners, shampoos, bath foams and for many other purposes. The present invention is concerned primarily with cleansers used for cleaning skin but is not limited to that application. The cleansers of interest are aqueous based and contain a mixture of surfactants.
In order to achieve controlled use of a liquid cleansing composition, it is desirable to have a somewhat viscous but pourable or pumpable product. A thin, watery product is too easily spilled and wasted when used and does not have good consumer acceptance. A number of high molecular weight polymeric materials have been used in a wide variety of aqueous based products in a thickening, gelling, suspending or protective colloid functionality. Certain nonionic polymers are also known to impart desirable skin feel characteristics to the product, notably guar gum and derivatives thereof (see EP-A-No. 67025). However, cleansing products formulated with the levels of surfactant and polymer necessary to provide satisfactory foaming, thickening and skin feel properties suffer from poor product solubility and viscosity characteristics, especially on storage at low temperatures. Moreover, the solubility and viscosity characteristics are further aggravated by the use of fatty acid alkanolamides which are customarily added to liquid cleansing compositions for suds-boosting purposes. These problems can be mitigated to some extent by adding substantial levels of alcoholic solvents such as ethanol and the like. Nevertheless, the resulting products are not only expensive but are technically undesirable because alcoholic solvents are believed to have a tendency to cause drying of the skin.
It has now been discovered that liquid cleansing products having desirable foaming, thickening and skin feel properties together with excellent formulation solubility and viscosity characteristics at both normal and low storage temperatures are provided by the use of polymeric thickening materials together with a mixed surfactant system comprising additive levels of specified nonionic ethoxylated aliphatic alcohols.